Wow, we are told that will rot the pressure treated off. Funny how things vary from region to region.
In the case you mention, if they want to be pricks, they'll have us pour a sonotube full of concrete with a galvanized post holder at the top, and mount to that.
That connection then, the post holder to the post, will provide nearly zero strength against the post falling over. Unless there is a very long sleeve that runs over the post, like several feet, the lateral strength of the system is ruined abd all you get is vertical strength.
I didn't plan on concrete backfill, just the footing cookie under the pole but the engineering was very certain that it was required. More than one structural engineer since I got three bids. To be fair, my location must design for 115 mph wind loads and the building is 30x60 so a lot of exposure on the big side with not much width.